Leading by solar example

MAN Truck & Bus has upgraded its Pinetown assembly plant to be one of the company’s most energy efficient and carbon neutral –100 percent CO2 neutral, in fact. How has this been achieved?

Well, in short, by using our planet’s most abundant resource – the sun. Employing banks of photovoltaic (PV) solar panels on the facility’s newly refurbished roof, the plant has not only met MAN’s global goal of reducing energy consumption and emissions levels, but surpassed it in the grandest style.

MAN’s global Climate Strategy aims to reduce carbon emissions at its production sites – in Europe, Africa, Asia and South America – by 25 percent by 2020 … The Pinetown plant (founded in 1962) has achieved 100-percent carbon neutrality and will, eventually, be able to be 100 percent energy independent.

“The company’s mission to reduce energy consumption and CO2 emissions in our production processes is the same all around the world,” explains Heiko Kayser, head of production at the MAN Pinetown Assembly Plant. “The different solutions are tailored to the area in which the individual plant is located. In South Africa there is a lot of wind and sun, so that the PV system is the most efficient for us.”

MD of MAN Truck & Bus SA, Geoff du Plessis, continues: “Environmental responsibility has strategic importance for MAN and the up-scaling of this factory, to sustainable energy supply, will further align us with customers who share the same agenda as us – to minimise their impact on the environment.”

Following a feasibility study in 2013, the decision was taken to replace all the facility’s old asbestos roofing with inverted box rib (IBR) sheeting to include transparent sheeting, so to allow more natural light into the building, and to carry the 6 300 m2 of PV panels. Solaray designed and installed the R10-million system in less than six months.

“The investment MAN has made in making our Pinetown plant a ‘green’ building is significant, not only in terms of our environmental protection, but also in terms of MAN’s commitment to investing in our region,” continues Du Plessis. “MAN has always been at the forefront of fuel efficiency, in terms of our trucks and buses, and we are now at the forefront of how these products are produced – in a carbon-neutral factory.”

Alan Swart, MD of Solaray, explains that state-of-the-art equipment was sourced; including inverters and solar panels from Europe, which are able to generate power even in cloudy conditions, as well as mounting equipment from China.

He explains how the system works: “A PV system converts sunlight into electricity, so output power is directly related to the sun’s power, and will vary with time of day, season and cloud cover. To stabilise the output power, there is a storage system, which provides an even average output, irrespective of these factors. This can be backed by batteries, or tied to the grid.

“The grid-tied system feeds excess power to the grid and draws back from it if demand cannot be met. This happens instantaneously, in either direction, without any interruptions.”

Inverters are used to convert DC current from the panels to AC current (at the standard 230 V). These have a number of safety features to allow maintenance workers protection from the system and grid.

This particular 580 kW grid-tied system is designed to produce 810 000 kilowatt hours (kWh) of power per annum – far in excess of the plant’s current needs. “Our current consumption is only 790 000 kWh,” explains Kayser. “Anything we produce over and above our needs is fed back to the eThekwini grid. The system prioritises the use of the available renewable energy provided by the PV system at all times. Should additional capacity ever be required, this energy will then be drawn from the grid.”

The system is exceptionally high-tech, being linked to a web-based monitoring system that reports daily power consumption as well as electricity cost and CO2 savings. The online software also delivers exception reports enabling PV system issues to be rectified swiftly by Solaray (which is located just two kilometres away from the plant). Solaray is also contracted to undertake quarterly maintenance of the solar panels.

According to Kayser, by the end of this year, the plant will have saved a substantial R1 million in energy costs and 860 t of CO2 per annum. He expects these figures to improve as the years go by. However, the recent slew of environmental and waste management initiatives at the plant doesn’t end here …

In addition to the PV system, a wash bay with a water recycling system was installed. The system captures rainwater from the roof, which is stored in tanks alongside the wash bay. Water used is also pumped through an oil-water filtration system to be reused again. The water is not only used to clean the vehicles, but also to test the cabs for leaks once they are off the assembly line.

“Municipal water used to wash the vehicles, prior to the installation of the water recycling system, was discharged into the storm water system as waste water via a SOG tank (Sand/Oil/Grease trap) to ensure no environmental harm occurs,” explains Lynette Kühn, SHEQ manager at MAN Pinetown. “Approximately 60 to 70 kl – 30 percent of total water usage at the plant – was utilised for the washing of trucks; with the new recycling system this should now be the saving. Water used during the washing process is pumped back into the storage tanks via the SOG pit. Rain water from the roof is channelled into the storage tanks as well to supplement available water.”

A new worker-friendly finishing spray booth was also built during December, to ensure heightened levels of paint quality and control the emissions into the atmosphere from this part of the production process.

Kühn was the project manager for the solar conversion process. For her, all these initiatives demonstrate the company’s commitment to corporate social responsibility and environmental protection.

“MAN Pinetown, being a CO2-neutral assembly plant and using water more responsibly, is setting a new benchmark for sustainability in the automotive industry in Africa,” she remarks proudly.

In fact, this pride is clear on the faces of every MAN employee. The local operation has set an exceptional example for its international colleagues and industry counterparts to follow.